A new analysis by a University of Washington researcher suggests that higher temperatures have been taking a toll on water supplies from Northwest mountain snowpacks for four decades.

The study, by Philip Mote, a research scientist with the Pacific Northwest Climate Impacts Group at the UW, examined snowpack measurements across four states and British Columbia from 1950 through 1992. The research found that the amount of water contained in the snowpacks declined throughout the region -- as much as 60 percent in some places.

"These trends have profound and disturbing implications for water resources in the region, where conflicts over water have already drawn national attention," he said.

Higher temperatures are the main culprit for the lower water content -- called "snow-water equivalent" -- although in some areas, lower levels of precipitation also contributed, he said.

The study relied on snowpack measurements taken on April 1 each year at 145 sites, at elevations between 3,000 to 9,000 feet above sea level. All but four sites showed decreases in the water content of the snowpack. In addition, 90 of the sites marked declines of 25 percent or more over the 42-year period.

Nine sites -- eight in Oregon and one in Washington's Olympic National Park on Hurricane Ridge -- showed drops in water content of at least 60 percent.

The findings back other researchers' warnings that higher temperatures in the future will lead to earlier spring meltoffs and reduced river flows. The measurements are a way of gauging the summer's water supply, he said, because "snow on the ground in the spring is the precursor to the streamflows when the weather warms and the snow melts."

"We're already looking at ways we can make do," he said, from increasing water storage to more conservation efforts. But there's already a concern for this year as the average snowpack in Washington is only about 63 percent of normal. The region could face a drought, he said, adding that "we're dangling on the edge right now."